A physiological study of Saksenaea vasiformis Saksena

Summary The physiological conditions governing growth and sporulation ofSaksenaea vasiformis Saksena, a fungus with outstanding morphological features quite peculiar for Mucorales, were determined. Earlier studies made byTiwari (1955) on a strain of the same species had shown that this fungus is incapable of sporulating on any synthetic medium normally employed for growing fungi.The fungus had been found to have a high tolerance for very low and high pH values. It showed maximum growth at two pH values, one near neutral point, at pH 6, and another at high alkaline pH value, i.e., pH 11. Reason for this behaviour of this fungus has already been discussed. The most suitable temperature for the growth of the fungus was found to be between 30–35° C.Nearly all the carbon, nitrogen and sulphur sources which generally favour growth of fungi were found to support vegetative growth of this fungus as well. However, sporulation in this fungus had peculiar nutritional needs. Only some of the carbon sources, viz., arabinose, rhamnose, sorbose, galactose, lactose and citric acid which supported poor growth, were found to support good or excellent sporulation. But it may be stated that not all carbon sources supporting poor growth could induce sporulation of the organism. Also none of the nitrogen or sulphur sources could induce the fungus to sporulate in presence of glucose as carbon source.